Possibly, indeed, we may go back much further and suggest an ulterior explanation not only of this, but of far earlier stages of somatic growth. It may all be due to the momentum of ancient modes of reproduction, now super- seded and abortive, but the tides of which still swell every tissue and cell, or as a kind of incipient internal incubation. All these energies that now enlarge the individual, formerly, and before the specialization of sperm and germ elements, proceeded to the very fecund formation of new generations by budding, division, etc. Now they are speciaHzed and coordinated for functions, some more and some less directly auxiliary to a more effective and less wasteful method of insuring offspring and of bringing each to a more complete maturity. Nature and education thus may have a new bio- logic explanation and meaning, and a deeper import, as limitation in fecundity is supplemented by the later functions of parenthood, which are transfigurations of what was origi- nally more primitive than sex itself, so that secondary sexual quaHties were once primary but are now diverted to higher uses. The ministry of nursing, protecting, providing for, and 44 THE PSYCHOLOGY OF ADOLESCENCE teaching the young is thus performed by the same impulses, now steriHzed and diverted, that once produced offspring. Thus the augmented individuaHty of adolescence is devel- oped in the interest of the species for the sake of which sex itself originally arose, and to serve which art, science, and re- ligion came into being, together with all the institutions which the powers acquired at this age have since created.
No explanation, however, of the stage of acceleration is complete without considering the lower plateau of growth at the age of from eight or nine to eleven or twelve, which precedes it. Some have argued that the later growth was a compensation for the preceding retardation and have even thought the two curves similar, though inverse. It has been urged that nature paused a while only to catch up later, and this has never been thought to demand any explanation save the commonplace view that first the organism husbands its resources to make a spring forward later. I think we must seek a cause for both these variations from a straight line of increment, and it is certain that the curves are not comple- mental, but that the later increase in rate is far more marked than the earHer decrease, and therefore can not be accounted for as merely making up for lost time.
The genetic explanation I propose here is the following: The period of retardation represents a relative balance be- tween assimilation and expenditure and, what is far more important, between fundamental growth of the large bones and muscles and the accessory development of the smaller and more peripheral parts and functions. Indeed, the boy of ten or eleven is tolerably well adjusted to the environment of savage life in a warm country where he could readily live independently of his parents, discharging all the functions necessary to his personal life, but lacking only the repro- ductive function. In his instincts, amusements, and associa- tions, his adjustment to such an environment is quite stable; his activity is at its greatest both in amount and variety, as studies to be later considered show. We shall later also see in how many of his ways he resembles the savage and how each furnishes the key for understanding both the good and bad points in the other's character. All this suggests on the recapitulation theory some long stationary period during GROWTH IN HEIGHT AND WEIGHT 45 which life had been pretty fully unfolded and could be led indefinitely and with stability and security in some not too cold Lemuria, New Atlantis, Eden, or other possible cunabit- lum gentium. This arrest may even suggest the age of senes- cence in some post-simian stage of ancestry. This short pause would thus be the present echo of a long phyletic stage when for many generations our prehuman forebears were pigmoid adults, leading short lives and dying at or before the pubic growth increment now occurs. It is no argument against this view that the boy of this age can not perpetuate his species, for this function is most of all mobile 'up and down the age scale by causes to some extent known and in some degree controllable.
Not only this, but hard conditions, like homelessness, imperfect food and health, and now sexual precocity develop strong tendencies to revert to or to remain in this stage. Kline has shown that truants are not only smaller but more akin to nomadic races than others; Dawson and many others, whose work will be later discussed, have pointed out how criminality is a product of augmentation of instincts normal at this age, but where the power to inhibit and repress does not develop, while the former grows to dangerous dimen- sions. Thus man, adult in years and stature, is constantly prone to drop to this lower level, development above which becomes a little more precarious than the preceding stages had been. The latter periods of growth are different and more insecure because newer and more unstable.
On this hypothesis we can perhaps inventory some of the influences which have contributed to the ascent of man to a more ample growth. First of all, selection favors large races and individuals; the latter would overcome others in the con- flicts of sexual competition and win the most desirable wives as well as the best food and all other advantages that strength could procure. Moreover, as migration has led man west and north into more rigorous climates, the tallest and largest have preceded as they still continue to go west. Perhaps competition is at first more severe in new regions and in high latitudes, where, as we have seen, men are usually larger, or these may have been the more enterprising in leading such advances of the race, just as tall dolichocephalic men still 4^ THE PSYCHOLOGY OF ADOLESCENCE now most frequently forsake the country for urban life. Again, the struggle with the saber-toothed tiger, the great cave bear, mastodon, Irish elks, gigantic sloths, and extinct vertebrates of the Quaternary age, may have been a factor in stimulating greater growth in man. The advent of the father to the family after the long period of matriarchate and per- haps the prolonged domestication of savage youth, who had be- fore tended to become feral at the dawn of adolescence due to paternal influences and subjection, the growth of the home, all agencies that tended to defer marriage, as civiliza- tion with its arts increased, while numbers and intensified struggle slowly augmented; these and many other factors need not have come altogether, but only to have been un- evenly distributed in order to constitute a curve of accel- eration.
Once more, adolescence is a period of rich and poly- morphic variations almost suggesting sports in all that per- tains to both primary and secondary sexual qualities. Vir- chow states that variations often thought pathological are normal at this age. The organism reassumes its more prim- itive power of all-sided development as if ids or determinants essentially contrary were struggling for survival or prepo- tency among themselves in the same individual. These vari- ables later become less independent and their range is reduced. This is all seen in the psychic field. The various equilibria of forces thus accurring, constitute the great oppor- tunity for the environment and for education. Cope, Scott, Bateson, Dollo, De Vries, and others,^ dissatisfied with the doctrine of gradual origin of species, have gathered facts from many fields suggesting that the variations which produce new species are sudden and discontinuous, and that these muta- tions, which may not be in only one but many directions at once, tend to show themselves in a species at certain periods separated by long intervals, when symptoms of a tendency to multiform variations, that are qualitative and not merely quantitative, arise and produce many individuals of a new kind within a short interval of time, so they can perpetuate themselves. The parent species then settles to its old lines, * Cf. especially De Vries. Entstehung der Arten durch Mutation, igoi.
GROWTH IN HEIGHT AND WEIGHT 47 possibly later to suffer competition and even extermination by their transpeciated descendants. However this may be for plants and animals, such mutation periods suggest something like an adolescence of the species in which they occur, and are analogous to the changes that take place in both the body and soul of youth at this age of all-sided and saltatory devel- opment, when new traits, powers, faculties, and dimensions, which have no other nascent period, arise. Galton ^ sup- poses that his midparent contributes two-thirds the pecul- iarity in height and that any peculiarity tends to regress to mediocrity. Thus again we come upon a suggestion that ado- lescence abounds in cases that need special explanation not covered by general laws.
We must therefore regard the preadolescent increment of growth as representing not only a later stage in the phy- logeny of modern man, but as marked off from previous stages, a little as the successive geologic strata are differen- tiated. Relatively to the periods that precede, man is now in a recent epoch, prolonged as it may have been, in which a new story has been added to his nature, so that he is now a super-man to his ancient forebears. A new being is born out of and superposed on the old, and in a new sense the boy is father to the man, and far older.
All this comports well with the greatly increased physical and mental instability which we find here. Young children grow despite great hardships, but later adolescence is more dependent upon favoring conditions in the environment, dis- turbances of which more readily cause arrest and prevent maturity. Not only is the range of variation in growth now increased, but there is far greater liability to reversion. As we advance to the later stages of adolescence, all these liabil- ities are greatly increased, as is the predisposition to sickness. The young pubescent, achieving his growth in the realm of fundamental qualities, dimensions, and functions, comes up to adult size at eighteen relatively limp and inept, like an insect that has just accomplished its last molt, and is therefore far more in the need of protection, physical care, moral and intel- lectual guidance; and in general, as will be considered later in * Family Likeness in Stature. Proc. Royal Soc. of I>ondon, vol. xl, p. 42.
48 THE PSYCHOLOGY OF ADOLESCENCE detail, this last great wave of growth throws the child up on to the shores of manhood or womanhood relatively helpless as from a second birth, rejuvenated, as if every cell in his body had striven to revive for the last time its failing reproductive potency. Through all these later stages of his growth, we can almost fancy that in the individual arrests and accelera- tions that make up its minor rhythms, we detect the ripple- marks on successive old shore-lines which represent once final stages of emergence to maturity, but which are now suc- cessively transcended.
This view will be strongly confirmed when we consider later the relatively independent character of boy life as com- pared with that of pubescence. Boys of ten lead a life with and for each other with less interest in adult life, yielding with what grace they may to the domination of " the Olym- pians," or adults, whose thoughts, purposes, and deeds often seem falsetto, unreal, and afar; but with adolescence, they become intensely susceptible to a wide range of adult influ- ences. Possibly some of the perturbations in the curve of growth for earlier years may mark yet older eons of maturity. Our adolescent phenomena may sometime be rep- resented by a series of oscillations between anagenic and cat- agenic processes, such as we now see in the perturbations at the age of six or seven, which suggest the ripple-marks of an old pubic beach, now at nearly every point submerged; so, too, our present period of maturity may sometime shrivel to a rudiment like the pause and finer adjustment at from nine to eleven or twelve, as childhood, youth, and apprentice- ship to life become prolonged in some ascendent super-race of the future. How many accelerations and retardations in height and weight are traces of ancient nodes where new buds were once set off we can not now tell, but I think that an indefinite perspective of these may sometime be determined. The pedigree of the horse is now pretty well traced from the polydactylous hippops, the size of a rabbit, up through the Eocene orohippus, the size of a fox, the miohippus of the Miocence age, the size of a sheep, the archihippus and proto- hippus of the Pliocene, the size of an ass, etc., with every indi- cation that at least its period of immaturity, if not its average age, has also increased. We can not prove that modern man GROWTH IN HEIGHT AND WEIGHT 49 was once adult at the size of the pigmy and that the boy repre- sents the height and weight of our forebears in a remote past, any more than we can disprove that he sprung from some extinct anthropoid the size of our smaller apes. Indeed, in the processes of evolution large phylogenetic stages may be represented by smaller ontogenetic ones, and our childhood be analogous to a dwindled, rudimentary organ. Our ances- tors may possibly have been, as an eminent anthropologist thinks, of Anakim size and perhaps have lived to a corre- spondingly great age. It is, of course, not demonstrably impossible that he may have had both a smaller stature and shorter life and then grown larger and lived longer than now, and again diminished, so that both increase and decrease in these respects may be atavistic or reversionary. However this be, two things seem more certain: first, that the relative size and age of reproduction must have been a factor, and, in some way not yet known, a concomitant variant; and, second, that at every stage, and especially since the period when the evolutionary struggle began to be predominantly psychic instead of physical, it is in psychic yet more than in physical rudiments that we must seek the key to unlock the enchanting but baffling mysteries of man's past in these respects, of which the soul, even more than the cells and organs, is full of dim echoes and reverberations.
Dominant in all these aspects of adolescence is the note of an equilibrium relatively less secure than what has pre- ceded, of an old anchorage broken, of elements less harmo- nized, of coordinations yet incomplete, of adjustments to the environment less fine and less settled, of insecurity and ever- impending danger of mental or physical relapse, and at the same time, of the promises and potencies of a slow but ever higher development. Hence there is need of the most careful ' study of consummate practical wisdom, in providing the most favorable environment and eliminating every possible cause of arrest or reversion. This is indeed the practical problem of this book.
Could we solve the problems of adolescence, which these aspects of growth alone propound, and justly evaluate the cause of its great advance, we should thus best be able to settle the deeper problems of education in the large sense 5 50 THE PSYCHOLOGY OF ADOLESCENCE that considers it as coextensive with all the environment. Tentative as is now our knowledge, it is sufficient to gen- erate a deep optimism in the hope that man is yet in the making, that the best things have not yet happened in his history, and that perhaps his present stage is at the same time the point of departure of a yet higher one related to all that adolescence now gives, as it is to the stages that have pre- ceded. Assuming the bionomic law, infant growth means being loaded with paleoatavistic qualities in a manner more conformable to Weismannism, embryonic growth being yet purer, while the pubescent increment is relatively neoata- vistic. From this it would seem to follow that the more com- plete and established the maturity before offspring are pro- duced, the greater the probability of phyletic progress in successive generations. It would also seem to be probable that the environment, the influence of which is augmented somewhat in proportion as maturity is attained, would be felt by advan- cing the species, infinitesimally though it be in each generation, toward a more perfect development of its higher and later ac- quired powers. On Cope's view, the influence of the environ- ment in producing acquired characters transmissible by heredity is greatest on the soma during adolescence.^ At any rate, for those prophetic souls interested in the future of our race and desirous of advancing it, the field of adolescence is the quarry in which they must seek to find both goal and means. If such a higher stage is ever added to our race, it will not be by increments at any later plateau of adult life, but it will come by increased development of the adolescent stage, which is the bud of promise for the race.
* Primary Factors in Organic Evolution, p. 446.
CHAPTER II GROWTH OF PARTS AND ORGANS DURING ADOLESCENCE Change of Proportions — Growth of Bones; Arms; Legs; Thighs; Pelvis; Sitting Height and Trunk; Skull; Neck; Jaw; Teeth; Muscles; Heart; Veins and Arteries; the Blood; Changes in Circulation; Lungs and their Capacity; the Vital Index; Brain; Dermal and Intestinal Surfaces; Glands and their Action — Abnormalities of Growth; Harmonious Development and its Meaning.
When, instead of considering the body as a whole, we now pass within it or seek to weigh and measure single parts and organs, we are confronted by yet more difficult problems. Many of these determinations can, of course, be made only on the cadaver, and the data are still far too few for many final conclusions. Even the external measurements of parts, Hmbs, joints, etc., are less numerous, too often less accurate and less accordant with each other than those of the body as a whole. Very significant and practical facts, however, are already established.
First: The parts do not grow in equal ratio. If they did so, the infant would become a monster adult with an enor- mous head, with legs and arms too short, the body, espe- cially the belly, too thick, the trunk too long. The following table from Vierordt,^ although known to be inaccurate in Fold.
Kidneys 12 Skin 12 Salivary glands 10. 7 Spinal cord, 7 Thyroid gland.., 4.5 Brain, 3.7 Suprarenal capsules 0.9 Thymus...-J Fold.
Testes 60 Muscles 48 Pancreas 28 Skeleton 26 Lungs 20 Stomach and alimentary canal...20 Milts 18 Liver 13.6 Ovaries 13 Heart 12.5 some parts, is still as a whole the best we have to show how manifold the weight of certain organs increases from birth to maturity. The lungs, stomach, and milts only grow about * Physiol, des Kindesalters, p. 254.
51 52 THE PSYCHOLOGY OF ADOLESCENCE as much as does the body as a whole; while testes and mus- cles greatly exceed, the thymus, eye, etc., grow far less than the total body. Many rudimentary parts, not mentioned in the preceding table, of which Wiedersheim describes several score which make the body Hke an old curiosity-shop, decline, and some even vanish with increasing age, so that at maturity our component parts are normally very different in their relative size from what they are at birth. Were we able to construct an analogous table showing the relative increase of organs from the first intrauterine month to the mature fetus, we should find very different and greater changes as well as more in number. Where single parts continue to grow too fast or exceed their normal proportions, and others fall behind or cease to grow, we have data for the very inter- esting science of teratology, in which the due balance and harmony of growth has been disturbed, and some parts are hypertrophied and others atrophied.
This is also seen although in general to a less extent in ex- ternal dimensions.
Growth in Lengths.
Vertex to the orbital margin.. Orbital margin to the larynx..
Larynx to the axilla Axilla to the crest of the ischium Upper arm, Lower arm Hand Sum of the above three.. Ischial crest to the knee. Knee to the foot sole..., Length of foot Age.
Total growth to Tsth Atbirth.
M.
year.
O.I Growth in Breadths.
Agb.
Total growth Further Atbirth.
to 15th year.
growth, • Head Q-'T 4 I Neck 6 13 10 10 3 3 6 7 5 5 3 3 0 9 5 I 3 6 3 5 8 3 7 2 22 15 17 5 5 3 5 3 9 7 Shoulders Thorax at the level of the prsecordia Hips at the level of the trochanter. Greatest breadth of calf Greatest breadth of foot PARTS AND ORGANS DURING ADOLESCENCE 53 The table on page 52 (Zeissing-Vierordt) shows the abso- lute growth in length and breadth in centimeters.
The opposite chart is a combination of two from Vierordt (Physiol, des Kindesalters, pp. 271, 274) showing, on the basis of Liharzik's measurements, nineteen dimensions for four ages, viz.: at birth, one year and nine months, fourteen years and three months, and twenty-five. This is drawn to scale in such a way that, starting from the left vertical line the distances along the four horizontal lines are in each case one-fifth those of the average individual.
Dr. W. W. Hastings ^ concludes that " the nearer an indi- vidual approaches mean development in height, the more nearly will he conform to an absolute standard of symmetry in his entire development. But there is a typical development and standard of symmetry for each height of each age, a standard which is attainable and to which the muscular development of the individual of that height may be made to conform very closely through the aid of systematic physical training and general care of health."
A good picture of the growth of the body as a whole and of its special external dimensions is presented in the cut on page 54 from Godin,^ who sought to determine the adolescent type at different pubescent years by 36,000 measurements on one hundred French schoolboys, followed individually from thirteen to eighteen years of age. By comparing the eighteen points de repere here represented by dots, the changes of pro- portion can be traced and measured on a millimetric scale.
Second: Few parts grow steadily, so that their develop- ment is represented not by straight lines but by curves which differ greatly one from the other in the same person and also differ in different individuals in whom the summative meas- ures of gross height and weight may coincide. The brain, e. g., almost ceases to increase in size or weight before pu- berty, when reproductive organs, hips, and muscles then grow at an augmented rate. The age of most rapid growth in any * See his Manual for Physical Measurements, with anthropometric tables for each height of each age and sex from five to twenty years, and vitality coefficients. 1902. The best manual of its kind.
' Recherches Anthropom^triques sur la croissance des diverses parties du corps.
54 THE PSYCHOLOGY OF ADOLESCENCE part is called its nascent period. While pubertal growth reaches more or less simultaneously nearly every part of the body, even its energies focus upon certain organs more than Millrmeters Others, and not a few sequences, to be later noted, are estab- lished, and more detailed and accurate measurements will probably add to this number. To determine these periods, PARTS AND ORGANS DURING ADOLESCENCE 55 not only for different parts, but for different traits and powers of the soul, is one of the chief quests of genetic study, and where established, the result is fraught with most important practical results.
Third: Not only do different parts reach their maximal size at different ages, but some continue to grow well on into old age. A recent writer concludes that the kidneys are at their largest in the third decade, the muscles, skeleton, intes- tines, and liver in the fifth, the heart and lungs in the eighth; and from this it would seem almost as if each organ has its youth, maturity, and old age, and that these do not coincide either with each other or with the stages of body growth as a whole. The motor organs as the heaviest give to growth its chief character, so that what we call maturity is the period of their greatest development. The body-weight as a whole sinks in old age despite the growth of lungs, intestines, heart, and liver, chiefly because the muscles and bones decline. Man is therefore not old because all the parts of his body are old, but because his heaviest organs decline. There is therefore no ab- solute standstill of growth, and age is relative, some organs re- maining young, and some achieving their highest rate of growth and nearly or quite ceasing before others attain their most rapid rate.